Collect specimens from the Tecumseh, Michigan, population for isolation of influenza viruses, including influenza A/NJ and other strains. Examine the serum bank maintained on Tecumseh residents to determine if A/NJ has appeared in in previous years in this population and also determine what other influenza viruses have been circulating in that population. The purpose of this retrospective serology will be to gain insight into the seeding process of influenza viruses in a community.